A point cloud projection system based on a single-chip superlens

Abstract

The present application provides a point cloud projection system based on a single-chip super lens. Along the direction of the optical axis of the point cloud projection system, the point cloud projection system includes in sequence: a light source array; a super lens; the light source array includes at least two off-axis sub-light sources located outside the optical axis; when the emitted light of the off-axis sub-light sources is emitted from the super lens, each of the main rays is deflected toward the optical axis, and the deflection angle of each main ray relative to the optical axis is positively correlated with the vertical distance of each exit position on the super lens relative to the optical axis; any two off-axis sub-light sources symmetrically distributed relative to the optical axis have the intersection of their respective main rays of emitted light located on the optical axis; and the divergence angle of the emitted light of the off-axis sub-light source when it is emitted from the super lens is less than the divergence angle of the corresponding emitted light when it is incident on the super lens. The point cloud projection system provided by the present application can improve the collimation of the emitted light to a higher level with only one super lens, thereby reducing the volume and cost of the point cloud projection system.

Description

Technical Field

[0001] The present application relates to the field of lenses, and in particular to a point cloud projection system based on a single-chip superlens. Background Art

[0002] In depth sensing related applications, whether using TOF (Time Of Flight) technology for depth sensing or structured light technology for depth sensing, the transmitter needs to project the emitted light of the light source into a light spot array containing multiple light spots. In order to increase the sensing distance of depth sensing, the divergence angle of the emitted light can be reduced (that is, the collimation of the emitted light can be improved). In order to increase the collimation of the emitted light to a higher level, the point cloud projection system provided by the related technology usually requires the use of multiple optical lenses to cooperate with each other. However, the use of multiple optical lenses makes the point cloud projection system provided by the related technology larger in size and higher in cost. Utility Model Content

[0003] One purpose of the present application is to propose a point cloud projection system based on a single-chip metalens, which can improve the collimation of the emitted light to a higher level with only one metalens, thereby reducing the size and cost of the point cloud projection system.

[0004] According to one aspect of an embodiment of the present application, a point cloud projection system based on a single-chip metalens is disclosed. Along the direction of the optical axis of the point cloud projection system, the point cloud projection system sequentially comprises: a light source array; a metalens;

[0005] The light source array includes at least two off-axis sub-light sources located outside the optical axis;

[0006] When the emitted light of the off-axis sub-light source is incident on the metalens, each principal ray is perpendicular to the metalens; when the emitted light of the off-axis sub-light source is emitted from the metalens, each principal ray is deflected toward the optical axis, and the deflection angle of each principal ray relative to the optical axis is positively correlated with the vertical distance of each exit position on the metalens relative to the optical axis;

[0007] For any two off-axis sub-light sources symmetrically distributed relative to the optical axis, the intersection of the main rays of their respective emitted lights is located on the optical axis; and the divergence angle of the emitted light of the off-axis sub-light source when it emerges from the superlens is smaller than the divergence angle of the corresponding emitted light when it is incident on the superlens.

[0008] In an exemplary embodiment of the present application, the light source array further comprises: an on-axis sub-light source located on the optical axis;

[0009] The principal ray of the light emitted by the on-axis sub-light source always overlaps with the optical axis;

[0010] The divergence angle of the emitted light of the on-axis sub-light source when it emerges from the super lens is smaller than the divergence angle when it is incident on the super lens.

[0011] In an exemplary embodiment of the present application, the structural surface where the micro-nano structure in the superlens is located includes a plurality of micro-nano structures stacked in a direction perpendicular to the superlens.

[0012] In an exemplary embodiment of the present application, the structural surface where the micro-nano structure in the superlens is located is only provided on the front surface of the superlens facing the light source array, or only provided on the rear surface of the superlens facing away from the light source array.

[0013] In an exemplary embodiment of the present application, the point cloud projection system satisfies the following conditional formula: 1m >f*tan(δ F )+y F ;

[0014] Among them, R 1m is the effective area radius of the first structural surface of the metalens; f is the focal length of the metalens; δ F y is the divergence angle of the emitted light of the sub-light source when it is emitted from the sub-light source; F is the radius of the effective light emitting area of ​​the light source array;

[0015] When the structural surface of the super lens is only provided on the front surface of the super lens facing the light source array, the first structural surface is the structural surface provided on the front surface; when the structural surface of the super lens is only provided on the rear surface of the super lens facing away from the light source array, the first structural surface is the structural surface provided on the rear surface.

[0016] In an exemplary embodiment of the present application, the structural surface where the micro-nano structure in the superlens is located is arranged on the front surface of the superlens facing the light source array, and is also arranged on the rear surface of the superlens facing away from the light source array.

[0017] In an exemplary embodiment of the present application, the point cloud projection system satisfies the following conditional formula:

[0018]

[0019] Wherein, L is the distance from the light source array to the front surface of the super lens facing the light source array; f is the focal length of the super lens.

[0020] In an exemplary embodiment of the present application, the point cloud projection system satisfies the following conditional formula with 2π radians per millimeter as a unit:

[0021]

[0022]

[0023] Among them, D 1m θ is the effective area diameter of the first structural surface where the micro-nano structure in the superlens is located; 1max is the maximum absolute value of the phase difference provided by the first structural surface within the corresponding effective area at the central wavelength of the working band; θ 1max / 2 is the maximum absolute value of the phase difference provided by the first structural surface within the half radius range of the corresponding effective area at the central wavelength; the half radius range is the range covered by the center of the circumscribed circle of the corresponding effective area to the half radius position of the circumscribed circle of the corresponding effective area;

[0024] When the structural surface of the super lens is only provided on the front surface of the super lens facing the light source array, the first structural surface is the structural surface provided on the front surface; when the structural surface of the super lens is only provided on the rear surface of the super lens facing away from the light source array, the first structural surface is the structural surface provided on the rear surface; when the structural surface of the super lens is provided on both the front surface and the rear surface, the first structural surface is the structural surface provided on the front surface.

[0025] In an exemplary embodiment of the present application, when the structural surface where the micro-nano structure in the metalens is located is provided on both the front surface and the rear surface, the structural surface provided on the rear surface is the second structural surface of the metalens; the point cloud projection system also satisfies the following conditional formula with 2π radians per millimeter as a unit:

[0026]

[0027]

[0028] Among them, D 2m is the effective area radius of the second structural surface; θ 2max is the maximum absolute value of the phase difference provided by the second structural surface within the corresponding effective area at the central wavelength; θ 2max / 2 It is the maximum absolute value of the phase difference provided by the second structural surface within the half radius range of the corresponding effective area at the central wavelength; the half radius range is the range covered by the center of the circumscribed circle of the corresponding effective area to the half radius position of the circumscribed circle of the corresponding effective area.

[0029] In an exemplary embodiment of the present application, the point cloud projection system satisfies the following conditional formula in millimeters:

[0030] Among them, y F is the radius of the effective light emitting area of ​​the light source array; θ F is the deflection angle of the emitted light of the edge sub-light source relative to the normal line of the super lens when it is emitted from the super lens; d F δ is the radius of the light spot projected by the sub-light sources in the light source array on the structural surface of the super lens; F is the divergence angle of the emitted light of the sub-light source when it is emitted from the sub-light source.

[0031] The point cloud projection system provided by the present application includes, along the direction of the optical axis of the point cloud projection system, the point cloud projection system in sequence: a light source array; a metalens. The light source array includes at least two off-axis sub-light sources located outside the optical axis. When the emitted light of the off-axis sub-light source is incident on the metalens, the respective principal rays are perpendicular to the metalens. When the emitted light of the off-axis sub-light source is emitted from the metalens, the respective principal rays are deflected toward the optical axis, and the deflection angle of the respective principal rays relative to the optical axis is positively correlated with the vertical distance of the respective emission position on the metalens relative to the optical axis; for any two off-axis sub-light sources symmetrically distributed relative to the optical axis, the intersection of the principal rays of their respective emitted light is located on the optical axis. When the metalens modulates the emitted light of the off-axis sub-light source in this way, the light modulation effect played by the metalens allows the metalens to be approximated as an ideal paraxial surface, and the light emitted from the ideal paraxial surface has a relatively high degree of collimation. Therefore, in the embodiment of the present application, the divergence angle of the emitted light of the off-axis sub-light source when it is emitted from the superlens is smaller than the divergence angle of the corresponding emitted light when it is incident on the superlens, and has a higher degree of collimation.

[0032] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0033] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and other objects, features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0035] Figure 1 The optical architecture diagram of the point cloud projection system based on a single-chip metalens provided in the present application is shown.

[0036] Figure 2 A schematic diagram showing, in the point cloud projection system provided in the present application, that the respective principal rays of the off-axis sub-light sources are deflected toward the optical axis when the emitted light is emitted from the superlens.

[0037] Figure 3An optical architecture diagram of a point cloud projection system provided in one embodiment of the present application is shown.

[0038] Figure 4 The figure shows an imaging point diagram obtained after the emitted light of sub-light sources at different positions of the light source array is modulated by a superlens in a point cloud projection system provided in one embodiment of the present application.

[0039] Figure 5 An optical architecture diagram of a point cloud projection system provided in one embodiment of the present application is shown.

[0040] Figure 6 The figure shows an imaging point diagram obtained after the emitted light of sub-light sources at different positions of the light source array is modulated by a superlens in a point cloud projection system provided in one embodiment of the present application.

[0041] Figure 7 An optical architecture diagram of a point cloud projection system provided in one embodiment of the present application is shown.

[0042] Figure 8 The figure shows an imaging point diagram obtained after the emitted light of sub-light sources at different positions of the light source array is modulated by a superlens in a point cloud projection system provided in one embodiment of the present application.

[0043] Fig. 9 An optical architecture diagram of a point cloud projection system provided in one embodiment of the present application is shown.

[0044] Fig.10 The figure shows an imaging point diagram obtained after the emitted light of sub-light sources at different positions of the light source array is modulated by a superlens in a point cloud projection system provided in one embodiment of the present application.

[0045] Fig.11 An optical architecture diagram of a point cloud projection system provided in one embodiment of the present application is shown.

[0046] Fig.12 The figure shows an imaging point diagram obtained after the emitted light of sub-light sources at different positions of the light source array is modulated by a superlens in a point cloud projection system provided in one embodiment of the present application.

[0047] Fig.13 An optical architecture diagram of a point cloud projection system provided in one embodiment of the present application is shown.

[0048] Fig.14 The figure shows an imaging point diagram obtained after the emitted light of sub-light sources at different positions of the light source array is modulated by a superlens in a point cloud projection system provided in one embodiment of the present application.

[0049] Reference numerals:

[0050] 1-light source array; 2-superlens; 3-observation screen. DETAILED DESCRIPTION

[0051] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present application will be more comprehensive and complete and the concepts of the example embodiments will be fully conveyed to those skilled in the art. The accompanying drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0052] In addition, the described features, structures or characteristics may be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present application. However, those skilled in the art will appreciate that the technical solution of the present application may be practiced while omitting one or more of the specific details, or other methods, components, steps, etc. may be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the present application and making the various aspects of the present application obscure.

[0053] Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0054] TOF technology is mostly used for long-distance depth sensing; for example, a laser radar is installed in a mobile phone or a vehicle. The laser radar, as the transmitter, projects a light spot array to the surrounding environment, and then the receiver senses the projected light spot array to obtain point cloud data. Finally, the processor obtains the depth information of the surrounding environment based on the time interval from the projected light spot to the sensed light spot, combined with the point cloud data, to perform depth sensing of the surrounding environment. Structured light technology is mostly used for close-range depth sensing; for example, the transmitter in a mobile phone projects a light spot array to a face, and then the receiver senses the projected light spot array to obtain point cloud data. Finally, the processor obtains the depth information of the face based on the deformation / displacement caused by the light spot, thereby performing depth sensing of the face, which is then used for face recognition.

[0055] It can be seen that whether using TOF technology or structured light technology, in order to perform depth sensing, the transmitter needs to project a light spot array containing multiple light spots.

[0056] It is understandable that the emitted light of a single sub-light source usually has a certain divergence angle. In this case, as the propagation distance of the emitted light continues to increase, the area of ​​the light spot also continues to increase. Moreover, the larger the divergence angle, the faster the light spot area will increase, which will cause adjacent light spots to overlap at a shorter propagation distance, and will also cause the brightness of the light spot to decrease faster and faster. When adjacent light spots overlap, the depth information of different light spots interferes with each other, making it difficult to perform depth sensing; when the brightness of the light spot drops to a certain level, it is difficult for the receiving end to sense the light spot, which also makes it difficult to perform depth sensing.

[0057] It can be seen from this that reducing the divergence angle of the emitted light (i.e., improving the collimation of the emitted light) can reduce the speed at which the spot area increases with the increase in the propagation distance of the emitted light, and thus light spots with no overlap and meeting the brightness requirements can be projected at a longer distance, thereby increasing the sensing distance of depth sensing.

[0058] In order to improve the collimation of the emitted light to a higher level, the point cloud projection system provided by the related art usually needs to use multiple optical lenses to cooperate with each other. However, the use of multiple optical lenses makes the point cloud projection system provided by the related art larger in size and more expensive.

[0059] In order to overcome the above-mentioned defects of the related art, the present application provides a point cloud projection system based on a single metalens. The point cloud projection system provided by the present application can improve the collimation of the emitted light to a higher level with only one metalens, thereby reducing the volume and cost of the point cloud projection system.

[0060] Figure 1 The optical architecture diagram of the point cloud projection system based on a single-chip metalens provided in the present application is shown. Figure 2 FIG. 1 is a schematic diagram showing that, in the point cloud projection system provided by the present application, when the emitted light of the off-axis sub-light source is emitted from the super lens, the respective principal light rays are deflected toward the optical axis. Figure 1 , the optical axis S of the point cloud projection system provided by the present application passes through the center of the metalens 2 and is perpendicular to the metalens 2. Figure 1 The point cloud projection system includes: a light source array 1; a super lens 2.

[0061] The light source array 1 includes at least two off-axis sub-light sources located outside the optical axis S. Figure 1 as well as Figure 2 The sub-light source 11 and the sub-light source 12 are off-axis sub-light sources.

[0062] The superlens 2 includes a substrate and a superstructure unit located on the surface of the substrate, and a micro-nano structure is provided at the vertex and / or center of the superstructure unit; the filling material between the micro-nano structures is air or other materials that are transparent in the working band. The micro-nano structure in the superlens 2 can be a positive micro-nano structure or a negative micro-nano structure.

[0063] In the embodiment of the present application, when the emitted light of the off-axis sub-light source is incident on the super lens 2, the respective principal rays are perpendicular to the super lens 2. Figure 1 When the emitted light of the sub-light source 11 is incident on the superlens 2, its main light ray c1 is perpendicular to the superlens 2; similarly, when the emitted light of the sub-light source 12 is incident on the superlens 2, its main light ray c2 is also perpendicular to the superlens 2.

[0064] After the emission light of the off-axis sub-light source is incident on the metalens 2, it is modulated by the metalens 2 and then emitted from the metalens 2. In the actual application stage, the emission light emitted from the metalens 2 will be projected on the surface of the target object to be sensed to obtain a light spot array. In the design stage, in order to confirm the projection effect of the emission light emitted from the metalens 2, an observation screen 3 can be set at a certain distance after the metalens 2, and then used to observe the light spot array projected on the observation screen 3.

[0065] In the embodiment of the present application, when the emitted light of the off-axis sub-light source is emitted from the superlens 2, each principal light ray is deflected toward the optical axis S, and the deflection angle of each principal light ray relative to the optical axis S is positively correlated with the vertical distance of each exit position on the superlens 2 relative to the optical axis S.

[0066] That is, the greater the vertical distance of the exit position of the emitted light of the off-axis sub-light source on the metalens 2 relative to the optical axis S, the greater the deflection angle of its main light relative to the optical axis S when it is emitted from the metalens 2; conversely, the smaller the vertical distance of the exit position of the emitted light of the off-axis sub-light source on the metalens 2 relative to the optical axis S, the smaller the deflection angle of its main light relative to the optical axis S when it is emitted from the metalens 2.

[0067] The deflection angle of the main ray of the off-axis sub-light source relative to the optical axis S when the light emitted from the superlens 2 refers to the acute angle formed between the main ray and the optical axis S. Figure 2 When the emitted light of the sub-light source 11 is emitted from the super lens 2, the acute angle α formed between its principal ray c1 and the optical axis S is the deflection angle of the principal ray c1 relative to the optical axis S.

[0068] In the embodiment of the present application, for any two off-axis sub-light sources symmetrically distributed relative to the optical axis S, when their respective emitted lights are modulated by the superlens 2 and then emitted from the superlens 2, their respective main light rays will approach each other and then intersect at a point on the optical axis S. Figure 1, the sub-light source 11 and the sub-light source 12 are symmetrically distributed relative to the optical axis S. When the emitted light of the sub-light source 11 and the emitted light of the sub-light source 12 are modulated by the super lens 2 and then emitted from the super lens 2, their respective corresponding main light rays c1 and c2 approach each other and then intersect at point d on the optical axis S.

[0069] When the metalens 2 modulates the emitted light of the off-axis sub-light source in this way, the light modulation effect played by the metalens 2 allows the metalens 2 to be approximated as an ideal paraxial surface, and the light emitted from the ideal paraxial surface has a relatively high degree of collimation. Therefore, in the embodiment of the present application, the divergence angle of the emitted light of the off-axis sub-light source when it is emitted from the metalens 2 is smaller than the divergence angle of the corresponding emitted light when it is incident on the metalens 2, and has a higher degree of collimation. Specifically, the point cloud projection system provided in the embodiment of the present application can control the divergence angle of the emitted light of the off-axis sub-light source when it is emitted from the metalens 2 to be below 5.76mr (i.e., 5.76 milliradians).

[0070] It can be seen that in the embodiment of the present application, only one metalens 2 can improve the collimation of the emitted light of each off-axis sub-light source in the light source array 1 to a higher level, thereby reducing the volume and cost of the point cloud projection system.

[0071] It should be noted that, in the embodiments of the present application, unless otherwise specified, the divergence angle of the emitted light refers to the divergence angle measured in half angle.

[0072] In one embodiment, the light source array 1 further includes: an on-axis sub-light source located on the optical axis S. Whether before incident on the metalens 2 or after emitted from the metalens 2, the principal ray of the emitted light of the on-axis sub-light source always overlaps with the optical axis S. Moreover, the divergence angle of the emitted light of the on-axis sub-light source when emitted from the metalens 2 is smaller than the divergence angle when incident on the metalens 2, and also has a high degree of collimation.

[0073] In one embodiment, the distance from the light source array 1 to the rear surface of the metalens 2 facing away from the light source array 1 is less than 1.1 mm. The distance from the light source array 1 to the rear surface of the metalens 2 can also represent the total optical length TTL (Total Track Length) of the point cloud projection system.

[0074] In the embodiment of the present application, the structural surface of the superlens 2 refers to the surface where the superstructure unit in the superlens 2 is located, or the surface where the micro-nanostructure in the superlens 2 is located.

[0075] In one embodiment, the structural surface where the micro-nano structure in the metalens 2 is located includes a plurality of micro-nano structures stacked in a direction perpendicular to the metalens 2. The arrangement of the plurality of micro-nano structures enables the corresponding structural surface to provide a larger phase coverage range.

[0076] In one embodiment, the structural surface where the micro-nano structure in the superlens 2 is located is only provided on the front surface of the superlens 2 facing the light source array 1, or only provided on the rear surface of the superlens 2 facing away from the light source array 1.

[0077] Compared with being arranged on the rear surface of the superlens 2, when the structural surface of the superlens 2 is arranged on the front surface of the superlens 2, a larger distance can be maintained between the superlens 2 and the light source array 1, thereby providing a larger focusing space for the superlens 2.

[0078] Compared with being arranged on the front surface of the superlens 2, when the structural surface of the superlens 2 is arranged on the rear surface of the superlens 2, the emitted light will first pass through the substrate of the superlens 2 before reaching the structural surface. Since the refractive index of the substrate is greater than the refractive index of the air, the propagation distance of the emitted light in the medium (the medium includes the air between the light source array 1 and the front surface of the superlens 2; when the structural surface is arranged on the rear surface of the superlens 2, the medium also includes the substrate of the superlens 2) will be compressed, which is more conducive to shortening the total optical length TTL of the point cloud projection system.

[0079] In one embodiment, when the structural surface where the micro-nano structure in the metalens 2 is located is only provided on the front surface of the metalens 2 facing the light source array 1, or is only provided on the rear surface of the metalens 2 facing away from the light source array 1, the point cloud projection system provided by the present application satisfies the following conditional formula: R 1m >f*tan(δ F )+y F .

[0080] Among them, R 1m is the effective area radius of the first structural surface of the super lens 2. f is the focal length of the super lens 2. δ F is the divergence angle of the emitted light of the sub-light source when it is emitted from the sub-light source; that is, δ F is the divergence angle of the light emitted by the sub-light source that has not been modulated by the super lens 2. F is the radius of the effective light emitting area of ​​the light source array 1. When the structural surface of the super lens 2 is only provided on the front surface, the first structural surface is the structural surface provided on the front surface; when the structural surface of the super lens 2 is only provided on the rear surface, the first structural surface is the structural surface provided on the rear surface.

[0081] In this embodiment, R 1m >f*tan(δ F )+y F This conditional constraint enables the emitted light of all sub-light sources of the light source array 1 to be completely received and modulated by the first structural surface, thereby reducing the waste of light energy.

[0082] In one embodiment, the structural surface where the micro-nano structure is located in the metalens 2 is provided on the front surface of the metalens 2 facing the light source array 1, and is also provided on the rear surface of the metalens 2 facing away from the light source array 1. That is, in this embodiment, structural surfaces are provided on both the front and rear surfaces of the metalens 2. Compared with only providing structural surfaces on a single surface of the metalens 2, providing structural surfaces on both the front and rear surfaces of the metalens 2 improves the design freedom of the metalens 2, thereby further improving the collimation of the emitted light.

[0083] In one embodiment, in the point cloud projection system provided by the present application, the phase provided by the metalens 2 satisfies the following conditional formula:

[0084] Where r is the distance between any point on the metalens 2 and the center of the metalens 2. i is the order of the phase coefficient. i is the phase coefficient of the i-th order. N is the number of terms in the polynomial.

[0085] In one embodiment, the point cloud projection system provided by the present application satisfies the following conditional formula: Wherein, L is the distance from the light source array 1 to the front surface of the super lens 2 facing the light source array 1; f is the focal length of the super lens 2.

[0086] In this embodiment, the front surface of the superlens 2 may be provided with a structured surface or may not be provided with a structured surface; and when the front surface of the superlens 2 is provided with a structured surface, the rear surface of the superlens 2 may also be provided with a structured surface or may not be provided with a structured surface.

[0087] So, through This conditional constraint allows the focal length of the metalens 2 and the distance between the metalens 2 and the light source array 1 to meet the requirements for the positional relationship between the paraxial surface and the light source array 1 under the premise that "the metalens 2 can have only one surface with a structured surface, or can have structured surfaces on both the front and rear surfaces". This allows the metalens 2 to be further approximated as a paraxial surface, thereby enabling the emitted light modulated by the metalens 2 to have a high degree of collimation.

[0088] In one embodiment, when only the front surface of the metalens 2 is provided with a structured surface, preferably, within the tolerance range, the point cloud projection system satisfies the following conditional formula: For example, when the tolerance is 0.01, if If the value of is in the interval [0.99,1.01], it is considered that the point cloud projection system satisfies the conditional expression

[0089] In one embodiment, the point cloud projection system provided by the present application satisfies the following conditional formula with 2π radians per millimeter as a unit:

[0090]

[0091]

[0092] In this embodiment, D 1m is the effective area diameter of the first structural surface where the micro-nano structure in the superlens 2 is located, in millimeters.

[0093] When the metalens 2 is provided with a structural surface on only one surface, the first structural surface refers to the structural surface provided on this only surface (that is, when the structural surface of the metalens 2 is provided only on the front surface of the metalens 2, the first structural surface is the structural surface provided on the front surface; when the structural surface of the metalens 2 is provided only on the rear surface of the metalens 2, the first structural surface is the structural surface provided on the rear surface); when the metalens 2 is provided with structural surfaces on both the front and rear surfaces, the first structural surface refers to the structural surface provided on the front surface.

[0094] The effective area of ​​a structural surface refers to the area covered by the super-structural unit in the structural surface. The effective area diameter of a structural surface refers to the diameter of the circumscribed circle corresponding to the effective area of ​​the structural surface.

[0095] In this embodiment, θ 1max θ is the maximum absolute value of the phase difference provided by the first structural surface within the corresponding effective area at the central wavelength of the working band, in units of 2π radians. 1max / 2 The maximum absolute value of the phase difference provided by the first structural surface within the half radius range of the corresponding effective area at the central wavelength, in units of 2π radians. The half radius range is the range covered by the center of the circumscribed circle of the corresponding effective area to the half radius position of the circumscribed circle of the corresponding effective area; specifically, the center of the circumscribed circle of the effective area is denoted as o, and the half radius position of the circumscribed circle of the effective area is denoted as r 1 / 2 , then the radius of half of the effective area refers to o~r 1 / 2 This range.

[0096] In this embodiment, by as well as The constraints of these two conditional expressions enable the phase gradient distribution provided by the first structural surface of the metalens 2 within its effective area to approximately meet the requirement for the refractive effect required for the paraxial surface, thereby enabling the metalens 2 to be approximated as a paraxial surface due to the phase gradient distribution provided by its first structural surface, thereby enabling the emitted light modulated by the metalens 2 to have a high degree of collimation.

[0097] Preferably, in one embodiment, the point cloud projection system provided by the present application satisfies the following conditional formula with 2π radians per millimeter as a unit:

[0098]

[0099] In one embodiment, when the structural surface where the micro-nano structure in the metalens 2 is located is provided on both the front surface and the rear surface, the structural surface provided on the rear surface is the second structural surface of the metalens 2. The point cloud projection system provided in the present application also satisfies the following conditional formula with 2π radians per millimeter as a unit:

[0100]

[0101] Among them, D 2m θ is the effective area diameter of the second structural surface, in millimeters. 2max θ is the maximum absolute value of the phase difference provided by the second structural surface within the corresponding effective area at the central wavelength, in units of 2π radians. 2max / 2 The maximum absolute value of the phase difference provided by the second structural surface within the half radius range of the corresponding effective area at the central wavelength, in units of 2π radians. The half radius range is the range covered by the center of the circumscribed circle of the corresponding effective area to the half radius position of the circumscribed circle of the corresponding effective area.

[0102] In this embodiment, the as well as These two conditional expressions constrain the first structural surface, so that the phase gradient distribution provided by the first structural surface can approximately meet the requirements of the refractive effect required for the paraxial surface. as well as The constraints of these two conditional expressions enable the phase gradient distribution provided by the second structural surface of the metalens 2 within its effective area to optimize the phase gradient distribution provided by the first structural surface, thereby further satisfying the need for the paraxial surface to provide a refractive effect, thereby enabling the metalens 2 to be closer to the paraxial surface due to the phase gradient distribution provided by its first structural surface and the second structural surface, thereby enabling the emitted light modulated by the metalens 2 to have a high degree of collimation.

[0103] In one embodiment, the point cloud projection system provided by the present application satisfies the following conditional formula in millimeters:

[0104] In this embodiment, y F is the radius of the effective light emitting area of ​​the light source array 1. The effective light emitting area of ​​the light source array 1 refers to the area covered by the sub-light sources in the light source array 1. The radius of the effective light emitting area of ​​the light source array 1 refers to the radius of the circumscribed circle corresponding to the area covered by the sub-light sources in the light source array 1.

[0105] θ FIt is the deflection angle of the emitted light of the edge sub-light source relative to the normal of the metalens 2 when it is emitted from the metalens 2. The edge sub-light source refers to the sub-light source located at the edge of the light source array 1. It should be noted that, based on the ray tracing, the deflection angle of each light ray at multiple positions of the emitted light of the edge sub-light source relative to the normal of the metalens 2 can be determined, and then the deflection angle of each light ray relative to the normal of the metalens 2 can be integrated to obtain the deflection angle of the emitted light of the edge sub-light source relative to the normal of the metalens 2.

[0106] d F is the radius of the light spot projected by the sub-light sources in the light source array 1 on the structural surface of the metalens 2. Generally, the specifications of the sub-light sources in the light source array 1 are consistent, so the radius of the light spot projected by the sub-light sources on the structural surface is also consistent. It should be noted that when both the front and rear surfaces of the metalens 2 are provided with structural surfaces, d F It refers to the radius of the light spot projected by the sub-light source on the structural surface arranged on the front surface.

[0107] δ F is the divergence angle of the emitted light of the sub-light source when it is emitted from the sub-light source.

[0108] In this embodiment, by The constraint of this conditional formula enables the comprehensive convergence degree of the main light rays of the emitted light of all sub-light sources in the global range of the light source array 1 by the metalens 2 to be highly matched with the relative position relationship between the metalens 2 and the light source array 1, and thus can approximately meet the demand for the refractive effect required for the paraxial surface. As a result, the metalens 2 can be approximated as a paraxial surface due to the comprehensive refractive power it provides for the main light rays of the emitted light of all sub-light sources in the global range of the light source array 1, and thus the emitted light modulated by the metalens 2 can have a high degree of collimation.

[0109] The present application exemplarily provides, in 6 embodiments, a point cloud projection system that improves the collimation of emitted light to a higher level with only one metalens 2. Next, the 6 point cloud projection systems provided by the present application are introduced in detail.

[0110] Example 1

[0111] Figure 3 FIG. 1 shows an optical architecture diagram of the point cloud projection system provided in Example 1. Figure 3 The point cloud projection system provided in this embodiment includes, in sequence along the optical axis S direction: a light source array 1; and a super lens 2. In this embodiment, the structure surface is provided on the front surface of the super lens 2.

[0112] Table 1. System parameters of the point cloud projection system provided in Example 1

[0113] System Parameters data Diameter of the effective light emitting area of ​​the light source array 0.46mm Divergence angle when emitted from the sub-light source 15° Central wavelength of the operating band 940nm Total optical length (TTL) 1.09mm Divergence angle when emitting from the metalens <5.5mr

[0114] As can be seen from Table 1, the point cloud projection system provided in this embodiment has an effective light-emitting area diameter of 0.46 mm for the light source array 1; the divergence angle of the emitted light of each sub-light source when emitted from the sub-light source is 15°; the central wavelength of the emitted light of each sub-light source is 940 nm; the total optical length of the point cloud projection system is 1.09 mm; and the divergence angle of the emitted light of each sub-light source of the point cloud projection system when emitted from the super lens 2 is less than 5.5 mr.

[0115] Along the optical axis S direction, each surface in the point cloud projection system provided in this embodiment is numbered, and after summarizing the parameters of each surface, the following Table 2 is obtained.

[0116] Table 2. Parameters of each surface in the point cloud projection system provided in Example 1

[0117] Surface serial number Surface type Radius of curvature thickness Refractive Index 0 Spherical unlimited 0.37mm - 1 Metasurface unlimited 0.72mm 1.45～1.55 2 Spherical unlimited - -

[0118] Surface 0 is the plane where the light source array 1 is located. Surface 1 is the front surface of the super lens 2; since the structural surface is located on the front surface, the front surface is recorded as the super surface. Surface 2 is the back surface of the super lens 2.

[0119] As can be seen from Table 2, the radius of curvature of surface 0 is infinite (i.e., it is a plane), the distance between it and surface 1 is 0.37 mm, and the material between it and surface 1 is air. Surface 1 is a plane, the distance between it and surface 2 is 0.72 mm, and the refractive index of the material between it and surface 2 is between 1.45 and 1.55. Surface 2 is a plane.

[0120] Figure 4 The figure shows the imaging point diagrams obtained after the emitted light of the sub-light source at different positions of the light source array 1 is modulated by the super lens 2 in the point cloud projection system provided in Example 1. Specifically, the image plane data shown below each imaging point diagram refers to the divergence angle of the main light ray of the emitted light of the corresponding sub-light source (for example, "image plane: -0.649mr" means that the divergence angle of the main light ray of the emitted light of the corresponding sub-light source is 0.649mr); in order from left to right and from top to bottom, Figure 4 The imaging point diagram corresponding to the sub-light source at the center position of the light source array 1, the imaging point diagram corresponding to the sub-light source at the 1 / 3 radius position of the effective light-emitting area of ​​the light source array 1, the imaging point diagram corresponding to the sub-light source at the 2 / 3 radius position of the effective light-emitting area of ​​the light source array 1, and the imaging point diagram corresponding to the sub-light source at the edge position of the light source array 1 are respectively shown.

[0121] Depend on Figure 4It can be seen that in this embodiment, in the point cloud projection system, the light spots obtained by projecting the emitted light modulated by the superlens 2 are all within the range of the Airy disk (the radius of the Airy disk corresponds to a divergence angle of 5.76mr); and the divergence angle of the emitted light modulated by the superlens 2 is less than 5.5mr. It can be seen that the emitted light modulated by the superlens 2 has a high degree of collimation.

[0122] Example 2

[0123] Figure 5 FIG. 2 shows an optical architecture diagram of a point cloud projection system provided in Example 2. Figure 5 The point cloud projection system provided in this embodiment includes, in sequence along the optical axis S direction: a light source array 1; and a super lens 2. In this embodiment, the structure surface is provided on the rear surface of the super lens 2.

[0124] Table 3. System parameters of the point cloud projection system provided in Example 2

[0125] System Parameters data Diameter of the effective light emitting area of ​​the light source array 0.46mm Divergence angle when emitted from the sub-light source 15° Central wavelength of the operating band 940nm Total optical length (TTL) 0.50mm Divergence angle when emitting from the metalens <5.5mr

[0126] It can be seen from Table 3 that the point cloud projection system provided in this embodiment has an effective light-emitting area diameter of 0.46 mm for the light source array 1; the divergence angle of the emitted light of each sub-light source when emitted from the sub-light source is 15°; the central wavelength of the emitted light of each sub-light source is 940 nm; the total optical length of the point cloud projection system is 0.50 mm; and the divergence angle of the emitted light of each sub-light source of the point cloud projection system when emitted from the super lens 2 is less than 5.5 mr.

[0127] Along the optical axis S direction, each surface in the point cloud projection system provided in this embodiment is numbered, and after summarizing the parameters of each surface, the following Table 4 is obtained.

[0128] Table 4. Parameters of each surface in the point cloud projection system provided in Example 2

[0129] Surface serial number Surface type Radius of curvature thickness Refractive Index 0 Spherical unlimited 0.10mm - 1 Spherical unlimited 0.40mm 1.45～1.55 2 Metasurface unlimited - -

[0130] Similar to the description of Table 2, the details of Table 4 will not be repeated here.

[0131] Figure 6 The figure shows the imaging point diagram obtained after the emitted light of the sub-light sources at different positions of the light source array 1 is modulated by the super lens 2 in the point cloud projection system provided in Example 2. Specifically, in the order from left to right and from top to bottom, Figure 6The imaging point diagram corresponding to the sub-light source at the center position of the light source array 1, the imaging point diagram corresponding to the sub-light source at the 1 / 3 radius position of the effective light-emitting area of ​​the light source array 1, the imaging point diagram corresponding to the sub-light source at the 2 / 3 radius position of the effective light-emitting area of ​​the light source array 1, and the imaging point diagram corresponding to the sub-light source at the edge position of the light source array 1 are respectively shown.

[0132] Depend on Figure 6 It can be seen that in this embodiment, in the point cloud projection system, the light spots obtained by projecting the emitted light modulated by the superlens 2 are all within the range of the Airy disk (the radius of the Airy disk corresponds to a divergence angle of 5.76mr); and the divergence angle of the emitted light modulated by the superlens 2 is less than 5.5mr. It can be seen that the emitted light modulated by the superlens 2 has a high degree of collimation.

[0133] Example 3

[0134] Figure 7 The optical architecture diagram of the point cloud projection system provided in Example 3 is shown. Figure 7 The point cloud projection system provided in this embodiment includes, in sequence along the optical axis S direction: a light source array 1; and a super lens 2. In this embodiment, the structure surface is provided on the front surface of the super lens 2.

[0135] Table 5. System parameters of the point cloud projection system provided in Example 3

[0136] System Parameters data Diameter of the effective light emitting area of ​​the light source array 0.46mm Divergence angle when emitted from the sub-light source 15° Central wavelength of the operating band 840nm Total optical length (TTL) 1.09mm Divergence angle when emitting from the metalens <5.76mr

[0137] It can be seen from Table 5 that the point cloud projection system provided in this embodiment has an effective light-emitting area diameter of 0.46 mm for the light source array 1; the divergence angle of the emitted light of each sub-light source when emitted from the sub-light source is 15°; the central wavelength of the emitted light of each sub-light source is 840 nm; the total optical length of the point cloud projection system is 1.09 mm; and the divergence angle of the emitted light of each sub-light source of the point cloud projection system when emitted from the super lens 2 is less than 5.76 mr.

[0138] Along the optical axis S direction, each surface in the point cloud projection system provided in this embodiment is numbered, and after summarizing the parameters of each surface, the following Table 6 is obtained.

[0139] Table 6. Parameters of each surface in the point cloud projection system provided in Example 3

[0140] Surface serial number Surface type Radius of curvature thickness Refractive Index 0 Spherical unlimited 0.37mm - 1 Spherical unlimited 0.72mm 1.45～1.55 2 Metasurface unlimited - -

[0141] Similar to the description of Table 2, the details of Table 6 will not be repeated here.

[0142] Figure 8The figure shows the imaging point diagram obtained after the emitted light of the sub-light sources at different positions of the light source array 1 is modulated by the super lens 2 in the point cloud projection system provided in Example 3. Specifically, in the order from left to right and from top to bottom, Figure 8 The imaging point diagram corresponding to the sub-light source at the center position of the light source array 1, the imaging point diagram corresponding to the sub-light source at the 1 / 3 radius position of the effective light-emitting area of ​​the light source array 1, the imaging point diagram corresponding to the sub-light source at the 2 / 3 radius position of the effective light-emitting area of ​​the light source array 1, and the imaging point diagram corresponding to the sub-light source at the edge position of the light source array 1 are respectively shown.

[0143] Depend on Figure 8 It can be seen that in this embodiment, in the point cloud projection system, the light spots obtained by projecting the emitted light modulated by the superlens 2 are all within the range of the Airy disk (the radius of the Airy disk corresponds to a divergence angle of 5.76mr); and the divergence angle of the emitted light modulated by the superlens 2 is less than 5.76mr. It can be seen that the emitted light modulated by the superlens 2 has a high degree of collimation.

[0144] Example 4

[0145] Fig. 9 FIG. 4 shows an optical architecture diagram of a point cloud projection system provided in Example 4. Fig. 9 The point cloud projection system provided in this embodiment includes, in sequence along the optical axis S, a light source array 1 and a super lens 2. In this embodiment, the structural surface is provided on both the front surface and the rear surface of the super lens 2.

[0146] Table 7. System parameters of the point cloud projection system provided in Example 4

[0147] System Parameters data Diameter of the effective light emitting area of ​​the light source array 0.46mm Divergence angle when emitted from the sub-light source 15° Central wavelength of the operating band 940nm Total optical length (TTL) 0.91mm Divergence angle when emitting from the metalens <2mr

[0148] It can be seen from Table 7 that the point cloud projection system provided in this embodiment has an effective light-emitting area diameter of 0.46 mm for the light source array 1; the divergence angle of the emitted light of each sub-light source when emitted from the sub-light source is 15°; the central wavelength of the emitted light of each sub-light source is 940 nm; the total optical length of the point cloud projection system is 0.91 mm; and the divergence angle of the emitted light of each sub-light source of the point cloud projection system when emitted from the super lens 2 is less than 2 mr.

[0149] Along the optical axis S direction, each surface in the point cloud projection system provided in this embodiment is numbered, and after summarizing the parameters of each surface, the following Table 8 is obtained.

[0150] Table 8. Parameters of each surface in the point cloud projection system provided in Example 4

[0151] Surface serial number Surface type Radius of curvature thickness Refractive Index 0 Spherical unlimited 0.18mm - 1 Metasurface unlimited 0.73mm 1.45～1.55 2 Metasurface unlimited - -

[0152] Similar to the description of Table 2, the details of Table 8 will not be repeated here.

[0153] Fig.10 The figure shows the imaging point diagram obtained after the emitted light of the sub-light sources at different positions of the light source array 1 is modulated by the super lens 2 in the point cloud projection system provided by Example 4. Specifically, in the order from left to right and from top to bottom, Fig.10 The imaging point diagram corresponding to the sub-light source at the center position of the light source array 1, the imaging point diagram corresponding to the sub-light source at the 1 / 3 radius position of the effective light-emitting area of ​​the light source array 1, the imaging point diagram corresponding to the sub-light source at the 2 / 3 radius position of the effective light-emitting area of ​​the light source array 1, and the imaging point diagram corresponding to the sub-light source at the edge position of the light source array 1 are respectively shown.

[0154] Depend on Fig.10 It can be seen that in this embodiment, in the point cloud projection system, the light spots obtained by projecting the emitted light modulated by the superlens 2 are all within the range of the Airy disk (the radius of the Airy disk corresponds to a divergence angle of 5.76mr); and the divergence angle of the emitted light modulated by the superlens 2 is less than 2mr. It can be seen that the emitted light modulated by the superlens 2 has a high degree of collimation.

[0155] Example 5

[0156] Fig.11 FIG. 5 shows an optical architecture diagram of a point cloud projection system provided in Example 5. Fig.11 The point cloud projection system provided in this embodiment includes, in sequence along the optical axis S direction: a light source array 1; and a super lens 2. In this embodiment, the structure surface is only provided on the front surface of the super lens 2.

[0157] Table 9. System parameters of the point cloud projection system provided in Example 5

[0158] System Parameters data Diameter of the effective light emitting area of ​​the light source array 0.46mm Divergence angle when emitted from the sub-light source 10° Central wavelength of the operating band 940nm Total optical length (TTL) 1.08mm Divergence angle when emitting from the metalens <5.76mr

[0159] It can be seen from Table 9 that the point cloud projection system provided in this embodiment has an effective light-emitting area diameter of 0.46 mm for the light source array 1; the divergence angle of the emitted light of each sub-light source when emitted from the sub-light source is 10°; the central wavelength of the emitted light of each sub-light source is 940 nm; the total optical length of the point cloud projection system is 1.08 mm; and the divergence angle of the emitted light of each sub-light source of the point cloud projection system when emitted from the super lens 2 is less than 5.76 mr.

[0160] Along the optical axis S, each surface in the point cloud projection system provided in this embodiment is numbered, and after summarizing the parameters of each surface, the following Table 10 is obtained.

[0161] Table 10. Parameters of each surface in the point cloud projection system provided in Example 5

[0162] Surface serial number Surface type Radius of curvature thickness Refractive Index 0 Spherical unlimited 0.35mm - 1 Metasurface unlimited 0.73mm 1.45～1.55 2 Spherical unlimited - -

[0163] Similar to the description of Table 2, the details of Table 10 will not be repeated here.

[0164] Fig.12 The figure shows the imaging point diagram obtained after the emitted light of the sub-light sources at different positions of the light source array 1 is modulated by the super lens 2 in the point cloud projection system provided in Example 5. Specifically, in the order from left to right and from top to bottom, Fig.12 The imaging point diagram corresponding to the sub-light source at the center position of the light source array 1, the imaging point diagram corresponding to the sub-light source at the 1 / 3 radius position of the effective light-emitting area of ​​the light source array 1, the imaging point diagram corresponding to the sub-light source at the 2 / 3 radius position of the effective light-emitting area of ​​the light source array 1, and the imaging point diagram corresponding to the sub-light source at the edge position of the light source array 1 are respectively shown.

[0165] Depend on Fig.12 It can be seen that in this embodiment, in the point cloud projection system, the light spots obtained by projecting the emitted light modulated by the superlens 2 are all within the range of the Airy disk (the radius of the Airy disk corresponds to a divergence angle of 5.76mr); and the divergence angle of the emitted light modulated by the superlens 2 is less than 5.76mr. It can be seen that the emitted light modulated by the superlens 2 has a high degree of collimation.

[0166] Example 6

[0167] Fig.13 FIG. 6 shows an optical architecture diagram of a point cloud projection system provided in Example 6. Fig.13 The point cloud projection system provided in this embodiment includes, in sequence along the optical axis S direction: a light source array 1; and a super lens 2. In this embodiment, the structure surface is only provided on the front surface of the super lens 2.

[0168] Table 11. System parameters of the point cloud projection system provided in Example 6

[0169] System Parameters data Diameter of the effective light emitting area of ​​the light source array 0.46mm Divergence angle when emitted from the sub-light source 12° Central wavelength of the operating band 940nm Total optical length (TTL) 1.09mm Divergence angle when emitting from the metalens <5.76mr

[0170] It can be seen from Table 11 that the point cloud projection system provided in this embodiment has an effective light-emitting area diameter of 0.46 mm for the light source array 1; the divergence angle of the emitted light of each sub-light source when emitted from the sub-light source is 12°; the central wavelength of the emitted light of each sub-light source is 940 nm; the total optical length of the point cloud projection system is 1.09 mm; and the divergence angle of the emitted light of each sub-light source of the point cloud projection system when emitted from the super lens 2 is less than 5.76 mr.

[0171] Along the optical axis S, each surface in the point cloud projection system provided in this embodiment is numbered, and after summarizing the parameters of each surface, the following Table 12 is obtained.

[0172] Table 12. Parameters of each surface in the point cloud projection system provided in Example 6

[0173]

[0174]

[0175] Similar to the description of Table 2, the details of Table 12 will not be repeated here.

[0176] Fig.14 The figure shows the imaging point diagram obtained after the emitted light of the sub-light sources at different positions of the light source array 1 is modulated by the super lens 2 in the point cloud projection system provided by Example 6. Specifically, in the order from left to right and from top to bottom, Fig.14 The imaging point diagram corresponding to the sub-light source at the center position of the light source array 1, the imaging point diagram corresponding to the sub-light source at the 1 / 3 radius position of the effective light-emitting area of ​​the light source array 1, the imaging point diagram corresponding to the sub-light source at the 2 / 3 radius position of the effective light-emitting area of ​​the light source array 1, and the imaging point diagram corresponding to the sub-light source at the edge position of the light source array 1 are respectively shown.

[0177] Depend on Fig.14 It can be seen that in this embodiment, in the point cloud projection system, the light spots obtained by projecting the emitted light modulated by the superlens 2 are all within the range of the Airy disk (the radius of the Airy disk corresponds to a divergence angle of 5.76mr); and the divergence angle of the emitted light modulated by the superlens 2 is less than 5.76mr. It can be seen that the emitted light modulated by the superlens 2 has a high degree of collimation.

[0178] After summarizing the various parameters of the point cloud projection system provided in the above six embodiments, the following Table 13 is obtained. The display of Table 13 is mainly used to illustrate that the various conditions satisfied by the point cloud projection system provided in this application are all verified and supported by experiments.

[0179] Table 13. Parameters of the point cloud projection system provided in each embodiment

[0180]

[0181]

[0182] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. A point cloud projection system based on a single-chip superlens, characterized in that: Along the direction of the optical axis of the point cloud projection system, the point cloud projection system includes in sequence: a light source array; a super lens; The light source array includes at least two off-axis sub-light sources located outside the optical axis; When the emitted light of the off-axis sub-light source is incident on the metalens, each principal ray is perpendicular to the metalens; when the emitted light of the off-axis sub-light source is emitted from the metalens, each principal ray is deflected toward the optical axis, and the deflection angle of each principal ray relative to the optical axis is positively correlated with the vertical distance of each exit position on the metalens relative to the optical axis; For any two off-axis sub-light sources symmetrically distributed relative to the optical axis, the intersection of the main rays of their respective emitted lights is located on the optical axis; and the divergence angle of the emitted light of the off-axis sub-light source when it emerges from the superlens is smaller than the divergence angle of the corresponding emitted light when it is incident on the superlens.

2. The point cloud projection system according to claim 1, characterized in that: The light source array further comprises: an on-axis sub-light source located on the optical axis; The main ray of the light emitted by the on-axis sub-light source always overlaps with the optical axis; The divergence angle of the emitted light of the on-axis sub-light source when it emerges from the super lens is smaller than the divergence angle when it is incident on the super lens.

3. The point cloud projection system according to claim 1, characterized in that: The structural surface where the micro-nano structure in the superlens is located includes multiple layers of micro-nano structures stacked in a direction perpendicular to the superlens.

4. The point cloud projection system according to claim 1, characterized in that: The structural surface where the micro-nano structure in the superlens is located is only provided on the front surface of the superlens facing the light source array, or only provided on the rear surface of the superlens facing away from the light source array.

5. The point cloud projection system according to claim 4, characterized in that: The point cloud projection system satisfies the following condition: 1m >f*tan(δ F )+y F ; Among them, R 1m is the effective area radius of the first structural surface of the metalens; f is the focal length of the metalens; δ F y is the divergence angle of the emitted light of the sub-light source when it is emitted from the sub-light source; F is the radius of the effective light emitting area of ​​the light source array; When the structural surface of the super lens is only provided on the front surface of the super lens facing the light source array, the first structural surface is the structural surface provided on the front surface; when the structural surface of the super lens is only provided on the rear surface of the super lens facing away from the light source array, the first structural surface is the structural surface provided on the rear surface.

6. The point cloud projection system according to claim 1, characterized in that: The structural surface where the micro-nano structure in the superlens is located is arranged on the front surface of the superlens facing the light source array, and is also arranged on the rear surface of the superlens facing away from the light source array.

7. The point cloud projection system according to claim 1, characterized in that: The point cloud projection system satisfies the following conditional formula: Wherein, L is the distance from the light source array to the front surface of the super lens facing the light source array; f is the focal length of the super lens.

8. The point cloud projection system according to claim 1, characterized in that: The point cloud projection system satisfies the following conditional formula with 2π radians per millimeter as a unit: Among them, D 1m θ is the effective area diameter of the first structural surface where the micro-nano structure in the superlens is located; 1max is the maximum absolute value of the phase difference provided by the first structural surface within the corresponding effective area at the central wavelength of the working band; θ 1max / 2 is the maximum absolute value of the phase difference provided by the first structural surface within the half radius range of the corresponding effective area at the central wavelength; the half radius range is the range covered by the center of the circumscribed circle of the corresponding effective area to the half radius position of the circumscribed circle of the corresponding effective area; When the structural surface of the super lens is only provided on the front surface of the super lens facing the light source array, the first structural surface is the structural surface provided on the front surface; when the structural surface of the super lens is only provided on the rear surface of the super lens facing away from the light source array, the first structural surface is the structural surface provided on the rear surface; when the structural surface of the super lens is provided on both the front surface and the rear surface, the first structural surface is the structural surface provided on the front surface.

9. The point cloud projection system according to claim 8, characterized in that: When the structural surface where the micro-nano structure in the metalens is located is provided on both the front surface and the rear surface, the structural surface provided on the rear surface is the second structural surface of the metalens; the point cloud projection system also satisfies the following conditional formula with 2π radians per millimeter as a unit: Among them, D 2m is the effective area diameter of the second structural surface; θ 2max is the maximum absolute value of the phase difference provided by the second structural surface within the corresponding effective area at the central wavelength; θ 2max / 2 It is the maximum absolute value of the phase difference provided by the second structural surface within the half radius range of the corresponding effective area at the central wavelength; the half radius range is the range covered by the center of the circumscribed circle of the corresponding effective area to the half radius position of the circumscribed circle of the corresponding effective area.

10. The point cloud projection system according to claim 1, characterized in that: The point cloud projection system satisfies the following conditional formula in millimeters: Among them, y F is the radius of the effective light emitting area of ​​the light source array; θ F is the deflection angle of the emitted light of the edge sub-light source relative to the normal line of the super lens when it is emitted from the super lens; d F δ is the radius of the light spot projected by the sub-light sources in the light source array on the structural surface of the super lens; F is the divergence angle of the emitted light of the sub-light source when it is emitted from the sub-light source.

Images